After much tinkering with my ELS settings I have come to the conclusion that -5 Bass and 0 Treble, -1 Subwoofer are the optimal settings for the system. It took me a while to figure out that Bass behaved more like low mid with some added bass rather than what I had kept expecting. All the harshness seems to go away as you lower this setting, leaving you with good sound reproduction. -4 Bass may be preferable for some concerned with staging (also depending on seating position).

I have one upgrade: a sub in the trunk crossed over at 60-65Hz. It's the only place I would want the sound altered except radio or other low quality format (+1 Treble).